jsonify a SQLAlchemy result set in Flask [duplicate]

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It seems that you actually haven’t executed your query. Try following:

return jsonify(json_list = qryresult.all())

[Edit]: Problem with jsonify is, that usually the objects cannot be jsonified automatically. Even Python’s datetime fails 😉

What I have done in the past, is adding an extra property (like serialize) to classes that need to be serialized.

def dump_datetime(value):
    """Deserialize datetime object into string form for JSON processing."""
    if value is None:
        return None
    return [value.strftime("%Y-%m-%d"), value.strftime("%H:%M:%S")]

class Foo(db.Model):
    # ... SQLAlchemy defs here..
    def __init__(self, ...):
       # self.foo = ...
       pass

    @property
    def serialize(self):
       """Return object data in easily serializable format"""
       return {
           'id'         : self.id,
           'modified_at': dump_datetime(self.modified_at),
           # This is an example how to deal with Many2Many relations
           'many2many'  : self.serialize_many2many
       }
    @property
    def serialize_many2many(self):
       """
       Return object's relations in easily serializable format.
       NB! Calls many2many's serialize property.
       """
       return [ item.serialize for item in self.many2many]

And now for views I can just do:

return jsonify(json_list=[i.serialize for i in qryresult.all()])

Hope this helps 😉

[Edit 2019]:
In case you have more complex objects or circular references, use a library like marshmallow).

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